* {
    margin: 0;
    padding: 0;
}

li {
    list-style: none;
    transition: 0.5s;
}

.box {
    width: 700px;
    margin: 0 auto;
    position: relative;

}

.box ul {
    width: 700px;
    height: 400px;
    position: relative;

}

.box ul li {
    width: 100%;
    height: 100%;
    position: absolute;
    left: 0;
    top: 0;
    opacity: 0;
    text-align: center;
    line-height: 400px;
    font-size: 50px;
    border: 1px solid #000;
}

.box ul li img {
    width: 100%;
    height: 100%;

}

.box ul .on {
    opacity: 1;
}

.box .jianTo {
    width: 100%;
    height: 50px;
    display: flex;
    justify-content: space-between;
    position: absolute;
    left: 0;
    top: 50%;
    margin-top: -25px;
}

.box .jianTo span {
    width: 50px;
    height: 50px;
    font-size: 30px;
    line-height: 50px;
    background: rgba(0, 0, 0, 0.7);
    text-align: center;
    color: #f2f3ef;
    cursor: pointer;
}

.box ol {
    position: absolute;
    bottom: 0;
    display: flex;
    justify-content: center;
    width: 100%;
}

.box ol li {
    width: 30px;
    height: 30px;
    background-color: #f00;
    margin: 10px;
}

.box .active {
    background-color: green;
}